The primary purpose of the proposed studies is to identify pragmatic off-road measures of cognitive and visuospatial abilities that can be used to predict safe and unsafe driving abilities in elderly drivers at risk for impairments. The study will involve the use of comprehensive approach to evaluating automobile driving in at-risk drivers, through the study of neuropsychological test performances, state driving records, and driving performance in both a driving simulator and an instrumented vehicle. The instrumented vehicle ARGOS was designed to measure critical aspects of driver control in the field without the bias of a road test graded by a human observer. Predictions of driver fitness in older drivers will also be independently derived from and significantly enhanced by studies conducted on a driving simulator. High-fidelity simulations allow the presentation of computer-controlled scenarios that look, sound, and feel like the actual experience of driving over real terrain, yet are more reproducible than an actual road test. By implementing high-fidelity simulated collision avoidance scenarios, crash risk can be safely inferred through direct observations of driver behavior in emergency situations that cannot otherwise be evaluated, including "fatal errors" in the final moments preceding a crash. Approximately 165 community dwelling older adults (ages 60-90) who are legally licensed and still actively driving will be studied. Approximately 50 percent of these individuals will have had one or more vehicle crashes in the preceding five years. By analyzing the performance of these drivers in the simulator, on the road in ARGOS, through a comprehensive battery of cognitive tests and actual state driving records performance factors which best discriminate between safe and unsafe drivers will be objectively identified. One of the ultimate goals of this research is to develop fair and accurate criteria to predict driving ability in elderly populations at risk for cognitive disability.